The present invention relates to a switch module that switches between signal paths in accordance with the frequency band.
Electronic devices that transmit and receive signals by using multiple frequency bands are known. In such electronic devices, a switch module that switches between signal paths in accordance with the frequency band may be used. In this switch module, a signal of a certain frequency band may leak from a terminal other than a target output terminal. This may cause a device or a circuit connected to such a terminal to malfunction. In order to improve the performance of such a switch module, it is necessary to enhance isolation characteristics representing the degree of isolation between terminals.
Japanese Unexamined Patent Application Publication No. 2004-140696 discloses a single-pole n-throw (SPnT) radio-frequency switch circuit that switches between plural receive output terminals and a transmit input terminal. In this radio-frequency switch circuit, a switch is disposed between a receive output terminal and a receive circuit to turn a radio-frequency signal ON/OFF. When a transmit signal is input from a transmit circuit, this switch is turned OFF. This configuration makes it possible to reduce a leakage of a transmit signal into a receive circuit and to enhance isolation characteristics of the radio-frequency switch circuit.